A U-shaped honing abrasive strip and a preparation method thereof

Abstract

The application provides a U-shaped honing abrasive strip, which comprises a support layer and a working layer formed on the surface of the support layer; a U-shaped groove parallel to the long side is arranged in the short side direction of the honing abrasive strip; and the raw materials for preparing the working layer comprise, in percentage by mass, 10-15% of cobalt powder, 30-40% of copper powder, 10-15% of tin powder, 5-10% of iron powder, 20-30% of tantalum nitride and 5-25% of diamond; and the raw materials for preparing the support layer comprise copper powder, tin powder, silicon carbide, aluminum oxide and tungsten powder. The application also provides a preparation method of the U-shaped honing abrasive strip. The hardness and strength of the honing abrasive strip are improved by adding tantalum nitride in the working layer, and the generation of random patterns and multi-ribbed patterns can be reduced by arranging the U-shaped groove.

Description

Technical Field

[0001] This invention relates to the field of honing abrasive strip technology, and more particularly to a U-shaped honing abrasive strip and its preparation method. Background Technology

[0002] In the existing technology, conventional honing abrasive strips are silicon carbide abrasive strips or diamond abrasive strips, and the honing particles are diamond or silicon carbide. The bonding part usually uses copper powder, tin powder, etc. to ensure rapid sintering and uniform particle removal during honing. In the preparation process, in order to reduce the sintering temperature, cobalt powder and silver powder are added to the bonding material. Furthermore, in order to reduce costs, iron powder is added and the content of other components is reduced.

[0003] The aforementioned adhesive materials only provide rapid bonding or easily cause grain detachment during honing. The hardness of the bonded portion is relatively low, resulting in a short lifespan for the honing strips. Furthermore, the adhesive materials used in the bonded portion offer virtually no grinding or polishing effect, and the rapid grain detachment frequently leads to irregular patterns, causing the honing texture to fail to meet the requirements of China VI or China VII standards. Therefore, providing a suitable adhesive material for honing strips is of great significance for achieving the required honing texture. Summary of the Invention

[0004] The technical problem solved by this invention is to provide a U-shaped honing strip. The U-shaped honing strip provided by this application has high hardness and high strength, and can reduce the generation of random patterns and polygonal shapes.

[0005] In view of this, this application provides a U-shaped honing strip, comprising: a support layer and a working layer formed on the surface of the support layer; and a U-shaped groove parallel to the long side is provided in the short side direction of the honing strip;

[0006] The raw materials for preparing the working layer, by mass percentage, include: 10-15% cobalt powder, 30-40% copper powder, 10-15% tin powder, 5-10% iron powder, 20-30% tantalum nitride, and 5-25% diamond;

[0007] The raw materials for preparing the support layer include: copper powder, tin powder, silicon carbide, aluminum oxide, and tungsten powder.

[0008] Preferably, by mass percentage, the support layer contains 75-85% copper powder, 3-5% tin powder, 8-15% silicon carbide, 2-5% aluminum oxide, and 1-3% tungsten powder.

[0009] Preferably, in the working layer, the content of cobalt powder is 11-14%; and / or, the content of copper powder is 32-37%; and / or, the content of tin powder is 12-14%; and / or, the content of iron powder is 7-9%; and / or, the content of tantalum nitride is 22-28%; and / or, the content of diamond is 7-15%.

[0010] Preferably, in the support layer, the content of copper powder is 78-83%; and / or, the content of tin powder is 3.5-4.5%; and / or, the content of silicon carbide is 8.5-14%; and / or, the content of aluminum oxide is 3-4.5%; and / or, the content of tungsten powder is 1.5-2.5%.

[0011] Preferably, the ratio of the distance between the two parallel sides of the U-shaped groove to the width of the U-shaped groove is (1-2):6.

[0012] Preferably, in the working layer, the tantalum nitride has a particle size of 20–30 μm, and / or the cobalt powder, copper powder, tin powder, and iron powder each have a particle size of less than 100 μm; and / or the diamond has a particle size of 54–64 μm; and / or the diamond has a distribution density of 50–120 particles / mm² in the working layer. 2 .

[0013] Preferably, in the support layer, the particle sizes of the copper powder, the tin powder, and the tungsten powder are independently selected from those below 100 μm.

[0014] This application also provides a method for preparing the U-shaped honing strip, comprising the following steps:

[0015] S1) Mix the raw materials according to the proportion of the raw materials used to prepare the working layer to obtain the working layer mixture;

[0016] The raw materials are mixed according to the proportion of raw materials used in the preparation of the support layer to obtain the support layer mixture;

[0017] S2) After loading the working layer mixture and the support layer mixture into the mold, the mold is sealed with a cover plate; the working layer mixture is near the end of the cover plate, and the cover plate is a cover plate with protrusions corresponding to the U-shaped groove;

[0018] S3) The mixture after molding is sintered to obtain U-shaped honing strips.

[0019] Preferably, in step S1), the mixing time during the preparation of the working layer mixture is 10 to 30 minutes; and / or, the mixing time during the preparation of the support layer mixture is 10 to 30 minutes.

[0020] Preferably, in step S3), the sintering includes a first sintering, a second sintering, and a third sintering performed sequentially;

[0021] The first sintering temperature is 400-500℃, the holding time is 1-3 min, and the pressure is 15-25 MPa;

[0022] The second sintering temperature is 600-700℃, the holding time is 5-7 min, and the pressure is 28-32 MPa;

[0023] The third sintering temperature is 720–780℃, the holding time is 8–10 min, and the pressure is 35–45 MPa.

[0024] This application provides a U-shaped honing strip, comprising: a support layer and a working layer formed on the surface of the support layer, wherein a U-shaped groove parallel to the long side is provided in the short side direction of the honing strip; the raw materials for preparing the working layer, by mass percentage, include: 10-15% cobalt powder, 30-40% copper powder, 10-15% tin powder, 5-10% iron powder, 20-30% tantalum nitride, and 5-25% diamond; the raw materials for preparing the support layer include: copper powder, tin powder, silicon carbide, aluminum oxide, and tungsten powder; the U-shaped honing strip provided in this application increases the durability of the working layer and reduces wear by adding tantalum nitride to the working layer. The frequency of honing strip replacement is reduced. Meanwhile, cobalt powder, copper powder, tin powder, and iron powder act as binders to fix the diamond and tantalum nitride, ensuring uniform blasting of the honing strip during wear. The support layer serves to fix the honing strip during honing, and the addition of silicon nitride and aluminum oxide enhances its strength. Furthermore, the U-shaped groove in the honing strip allows coolant to fully penetrate the U-shaped notch during honing, reducing heat generated by high-speed friction and carrying away the grit produced during blasting, thus reducing irregular patterns and multi-faceted shapes. This improves both the quality and efficiency of the honing pattern. Attached Figure Description

[0025] Figure 1 A side view of the U-shaped honing strip provided for this invention;

[0026] Figure 2 A top-view photograph of the U-shaped honing strip provided for this invention;

[0027] Figure 3 A front-view photograph of the U-shaped honing strip provided for this invention;

[0028] Figure 4 This is a schematic diagram of the mold cover plate during the preparation of the U-shaped honing sanding strip of the present invention;

[0029] Figure 5This is a schematic diagram of the texture of the cylinder liner after honing with the U-shaped honing sand bar prepared in Example 1 of the present invention;

[0030] Figure 6 This is a schematic diagram of the texture of the cylinder liner after honing with the U-shaped honing sand bar prepared in Example 2 of the present invention;

[0031] Figure 7 This is a schematic diagram of the texture of the cylinder liner after honing with the U-shaped honing sand bar prepared in Example 3 of the present invention;

[0032] Figure 8 This is a schematic diagram of the texture of the cylinder liner after honing with the U-shaped honing sand bar prepared in Comparative Example 1 of the present invention;

[0033] Figure 9 This is a schematic diagram of the texture of the cylinder liner after honing with the U-shaped honing sand bar prepared in Comparative Example 3 of the present invention. Detailed Implementation

[0034] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and are not intended to limit the scope of the claims of the present invention.

[0035] Existing honing strips suffer from the following problems: low and unstable overall hardness, leading to frequent strip replacements and low efficiency; uneven honing texture; significant differences in thermal conductivity between diamond and the binder causing uneven heating of the strip, resulting in reduced durability; furthermore, the large amount of heat generated during honing cannot be dissipated in time, and the resulting sludge and oil residue cannot be removed promptly, easily causing irregular patterns and poor honing effect, while also easily producing multi-faceted textures. To address these problems, this application provides a U-shaped honing strip, which introduces nitrogen into the working layer... Tantalum oxide alters the composition of the raw materials in the honing strip, increasing its hardness and strength, thereby improving its wear resistance and corrosion resistance. This reduces the frequency of strip replacement, increases work efficiency, and lowers costs. Simultaneously, it improves the working environment by reducing dust and heat generated by the strip, protecting worker safety. Furthermore, the honing strip is designed with a U-shaped groove to ensure that sludge and contaminants generated during honing are promptly removed, while also providing excellent cooling and achieving a better, more uniform texture. This allows the honed engine emissions to meet China VI and China VII standards. Specifically, this invention discloses a U-shaped honing strip, comprising: a support layer and a working layer formed on the surface of the support layer; a U-shaped groove parallel to the long side is provided on the short side of the honing strip.

[0036] The raw materials for preparing the working layer, by mass percentage, include: 10-15% cobalt powder, 30-40% copper powder, 10-15% tin powder, 5-10% iron powder, 20-30% tantalum nitride, and 5-25% diamond;

[0037] The raw materials for preparing the support layer include: copper powder, tin powder, silicon carbide, aluminum oxide, and tungsten powder.

[0038] The U-shaped honing strip provided in this application includes a support layer and a working layer formed on the surface of the support layer. The working layer serves as the honing layer, and its raw materials include cobalt powder, copper powder, tin powder, iron powder, tantalum nitride, and diamond. Among these raw materials, the cobalt powder, copper powder, tin powder, and iron powder are all binders, primarily functioning to fix the wear-resistant particles (diamond and tantalum nitride) into shape and ensure uniform particle removal during the honing process. Specifically, the cobalt powder, as a binder, improves the hardness of the honing strip. Cobalt powder in the working layer exhibits good toughness and a low sintering temperature, and can alloy with iron, contributing to improved strength and overall performance of the honing strip. It also significantly increases the wear resistance of the honing strip, making it more suitable for high-load and severely worn honing applications. Since cobalt exists as a trivalent oxide on the surface of the honing strip in the working layer, it helps prevent corrosive media from penetrating into the honing strip matrix, thereby improving the corrosion resistance of the honing strip. The cobalt powder content is 10-15%, specifically 11-14%; for example, the cobalt powder content in this application is 10%, 11%, 12%, 13%, 14% or 15%.

[0039] Copper powder acts as a binder in honing abrasive strips. Copper can form tin bronze alloys with other alloys such as tin, which can improve the hardness and wear resistance of the honing abrasive strips. Simultaneously, copper has good ductility and plasticity, which helps the abrasive strip maintain its shape stability during processing. Furthermore, the addition of copper can change the phase composition and structure of the working layer, improving its density and stability; therefore, the addition of copper helps improve the corrosion resistance of the abrasive strip. The copper powder content is 30-40%, specifically 32-37%; for example, in this application, the copper powder content is 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, and 40%.

[0040] Tin powder primarily acts as a binder, forming tin bronze with copper powder and increasing the hardness of the working layer. Simultaneously, adding tin powder to the honing strip helps reduce rapid wear, thus extending its service life. It also improves corrosion resistance. The tin powder content is 10-15%, specifically 12-14%; for example, the tin powder content is 10%, 11%, 12%, 13%, 14%, or 15%.

[0041] Iron powder in honing abrasive strips primarily functions as a sintering and bonding agent, while also acting as a skeleton, thus improving the hardness and strength of the abrasive strips. Iron powder, combined with elements such as cobalt and copper, exhibits excellent wear resistance in honing abrasive strips, and the combination of iron and cobalt forms a protective layer, enhancing the corrosion resistance of the honing abrasive strips. The iron powder content is 5-10%, specifically 7-9%; for example, in this application, the iron powder content is 5%, 6%, 7%, 8%, 9%, and 10%.

[0042] In this application, the particle size of the cobalt powder, the copper powder, the tin powder, and the iron powder is individually less than 100 μm.

[0043] In summary, the cobalt powder, copper powder, tin powder, and iron powder mentioned above collectively affect the hardness, strength, wear resistance, and corrosion resistance of honing strips. By adding these raw materials and limiting their content, the overall performance of honing strips can be improved.

[0044] Diamond and tantalum nitride in the working layer, as wear-resistant particles, significantly affect the hardness, strength, wear resistance, and corrosion resistance of honing abrasive strips. Diamond primarily functions as a grinding and dressing material in honing abrasive strips; its high hardness and strength also enhance the overall hardness and strength of the abrasive strip. Diamond's excellent wear resistance allows the honing abrasive strip to maintain its sharpness for extended periods, prolonging its service life. Furthermore, diamond's good chemical stability makes it resistant to corrosion; therefore, diamond-containing abrasive strips maintain good performance even in humid or corrosive environments. The diamond content is 5% to 25%, specifically, the diamond content is 7% to 15%; for example, the diamond content in this application is 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, and 25%.

[0045] Tantalum nitride is an ultra-hard material with high hardness. As an additive in honing abrasive strips, tantalum nitride can increase the hardness of the abrasive strips, making them suitable for a wider range of grinding and cutting applications. The addition of tantalum nitride enhances the structural strength of the honing strips, making them more able to withstand the pressure and impact during grinding. Simultaneously, tantalum nitride improves the heat resistance of the honing strips, preventing performance degradation due to high temperatures. Tantalum nitride has excellent wear resistance, reducing wear during grinding, thus resulting in a longer service life and higher grinding efficiency for tantalum nitride-containing honing strips. Furthermore, tantalum nitride exhibits good stability in various chemical environments, resisting the erosion of moisture and other corrosive media; therefore, abrasive strips containing tantalum nitride maintain good performance even in corrosive environments. The tantalum nitride content is 20-30%, specifically 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, and 30%.

[0046] In this application, the tantalum nitride has a particle size of 20–30 μm, the diamond has a particle size of 54–64 μm, and the diamond distribution density in the working layer is 50–120 particles / mm. 2 Specifically, the diamond distribution density in the working layer is 60–110 diamonds / mm². 2 Furthermore, the diamond distribution density in the working layer is 85–100 diamonds / mm². 2 .

[0047] In summary, diamond and tantalum nitride, as important components or additives in honing strips, can significantly improve the hardness, strength, wear resistance, and corrosion resistance of honing strips.

[0048] In this application, the support layer only serves to fix the honing abrasive strip during the honing process. The addition of silicon carbide and alumina enhances the strength of the support layer, but it does not participate in the honing process itself; the working layer does. When the working layer is finished, the lifespan of the abrasive strip is also exhausted, thus reducing waste of the support layer and saving costs. The raw materials for preparing the support layer include: copper powder, tin powder, silicon carbide, alumina, and tungsten powder. Specifically, by mass percentage, the support layer contains 75-85% copper powder, 3-5% tin powder, 8-15% silicon carbide, 2-5% alumina, and 1-3% tungsten powder. Specifically, the copper powder content is 78%–83%; for example, in this application, the copper powder content is 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, and 85%. The tin powder content is specifically 3%, 3.5%, 4%, 4.5%, and 5%. The silicon carbide content is 8.5%–14%; for example, in this application, the silicon carbide content is 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, and 15%. The content of aluminum oxide is 3-4.5%; for example, the content of aluminum oxide in this application is 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, and 5%. The content of tungsten powder is 1.5-2.5%; for example, the content of tungsten powder in this application is 1%, 1.5%, 2%, 2.5%, and 3%.

[0049] In this application, the honing strip is a honing strip with a U-shaped groove. Specifically, a U-shaped groove parallel to the long side is provided along the short side of the honing strip. Along the long side, the U-shaped groove may completely or partially penetrate the short side. A detailed schematic diagram is shown below. Figures 1-3 ,in, Figure 1 This is a side view of a honing strip. Figure 2 This is a top view of a honing strip. Figure 3 This is a plan view of the honing strip. Specifically, the ratio of the distance between the two parallel sides of the U-shaped groove (groove width) to the width of the U-shaped groove is (1~2):6.

[0050] This application also provides a method for preparing the U-shaped honing strip, comprising the following steps:

[0051] S1) Mix the raw materials according to the proportion of the raw materials used to prepare the working layer to obtain the working layer mixture;

[0052] The raw materials are mixed according to the proportion of raw materials used in the preparation of the support layer to obtain the support layer mixture;

[0053] S2) After loading the working layer mixture and the support layer mixture into the mold, the mold is sealed with a cover plate; the working layer mixture is near the end of the cover plate, and the cover plate is a cover plate with protrusions corresponding to the U-shaped groove;

[0054] S3) The mixture after molding is sintered to obtain U-shaped honing strips.

[0055] In the preparation process of the U-shaped honing abrasive strip, a working layer mixture and a support layer mixture are first prepared. The mixing method is carried out in a manner known to those skilled in the art, and this application does not impose any special restrictions on it. Specifically, the working layer mixture and the support layer mixture can be mixed separately in a mixer. The mixing time is 10 to 30 minutes, specifically, the mixing time is 20 minutes.

[0056] This application then seals the mold with a cover plate after loading the working layer mixture and the support layer mixture into the mold; during the above-mentioned mold loading process, the support layer mixture is placed at the bottom of the mold, the working layer is laid flat on top of the support layer mixture, and the cover plate is a cover plate with protrusions corresponding to the U-shaped groove, specifically as follows: Figure 4 As shown, a U-shaped groove is formed on the honing strip.

[0057] Finally, the mixture after molding is sintered to obtain U-shaped honed sand strips. The sintering includes gradient sintering, specifically including a first sintering, a second sintering, and a third sintering performed sequentially. More specifically, the temperature of the first sintering is 400-500℃, the holding time is 1-3 min, and the pressure is 15-25 MPa; the temperature of the second sintering is 600-700℃, the holding time is 5-7 min, and the pressure is 28-32 MPa; the temperature of the third sintering is 720-780℃, the holding time is 8-10 min, and the pressure is 35-45 MPa.

[0058] In this application, the sintering is performed using a vacuum hot pressing sintering furnace; the specific process includes:

[0059] ① Sample placement: Place the mold containing the mixture into the corresponding position inside the furnace, tighten the screw to press the sample, and close the cover door;

[0060] ② Vacuuming: Turn on the vacuum pump switch and close the exhaust valve when the vacuum level reaches 200Pa;

[0061] ③ Set pressure, temperature and holding time: Use the stepped sintering molding method. The first stage temperature is set to 450℃, holding time is 3min, and pressure is set to 20MPa; the second stage temperature is set to 650℃, holding time is 5min, and pressure is set to 30MPa; the third stage temperature is set to 750℃, holding time is 8min, and pressure is set to 35MPa.

[0062] ④ Pressurization: After setting, turn on the press switch. When the pressure rises to 5 MPa, turn on the temperature control system power switch. At this time, the temperature will start to rise. When the set temperature is reached, hot pressing will begin. Finally, after three heating and constant temperature cycles, and pressure is added until the pressure reaches the maximum and the holding time is reached, the hot pressing sintering is completed.

[0063] ⑤ Cooling and demolding: After the entire process is completed, turn on the water chiller to cool the sand strip mold. After it has completely cooled, take out the sample.

[0064] The U-shaped honing abrasive strip provided in this application improves the overall hardness and strength of the abrasive strip by incorporating high-hardness, high-strength tantalum nitride powder particles. This ensures that the abrasive strip maintains a certain level of hardness and strength during grinding, allowing for uniform and slow shedding. Furthermore, the high hardness increases the uniformity and consistency of the grinding grooves. Additionally, the thermal conductivity of tantalum nitride is close to that of diamond, thus increasing the durability of the abrasive strip. The U-shaped groove design further reduces the generation of irregular patterns and multi-faceted shapes.

[0065] To further understand the present invention, the following embodiments illustrate the U-shaped honing strip and its preparation method provided by the present invention. The scope of protection of the present invention is not limited by the following embodiments.

[0066] Example 1

[0067] An economical and environmentally friendly U-shaped honing strip consists of a support layer and a working layer formed on the surface of the support layer;

[0068] The raw materials for preparing the working layer include: cobalt powder: 12%, copper powder: 35%, tin powder: 13%, iron powder: 7%, tantalum nitride: 25%, with a particle size of 20-30 μm for tantalum nitride and a particle size of less than 100 μm for the other raw materials; the balance is diamond with a particle size of D54.

[0069] The raw materials for preparing the support layer include: copper powder: 80%, tin powder: 4%, silicon carbide: 10%, aluminum oxide: 4%, and tungsten powder: 2%; the particle size of all the above raw materials is less than 100 μm;

[0070] The preparation method of U-shaped honing strips specifically includes the following steps:

[0071] 1. Mixing: Weigh the different components according to the above ratio of the working layer and the support layer raw materials. Put the working layer raw materials and the support layer raw materials into the mixer respectively. Start the mixer and mix for 20 minutes respectively to ensure that the different components of each layer are fully mixed to obtain the working layer mixture and the support layer mixture.

[0072] 2. Mold assembly:

[0073] ① Weigh 8.5g of the support layer mixture, spread it evenly in the mold, and then level it with a scraper;

[0074] ② Weigh 14g of working layer mixture, spread it evenly on top of the support layer mixture, and level it with a scraper;

[0075] ③ Cover the mold with a cover plate that has a horizontal plate in the middle with a height of 4mm and a width of 2mm;

[0076] 3. Sintering: Sintering is carried out using a vacuum hot-pressing sintering furnace. The specific operation and parameters are as follows:

[0077] ④ Sample placement: Place the mold containing the mixture into the corresponding position in the furnace, tighten the screw to press the sample, and close the cover.

[0078] ⑤ Vacuuming: Turn on the vacuum pump switch at this time, and when the vacuum reaches 200Pa, close the exhaust valve.

[0079] ⑥ Set pressure, temperature and holding time: Use the stepped sintering molding method. The first stage temperature is set to 450℃, holding time is 3min, and pressure is set to 20MPa; the second stage temperature is set to 650℃, holding time is 5min, and pressure is set to 30MPa; the third stage temperature is set to 750℃, holding time is 8min, and pressure is set to 35MPa.

[0080] ⑦ Pressurization: After setting, turn on the press switch. When the pressure rises to 5MPa, turn on the temperature control system power switch. At this time, the temperature will start to rise. When the set temperature is reached, hot pressing will begin. Finally, after three heating and constant temperature cycles, and pressure is added until the pressure reaches the maximum and the holding time is reached, the hot pressing sintering is completed.

[0081] ⑧ Cooling and Demolding: After the entire process is completed, turn on the water chiller to cool the sand strip mold. After it has completely cooled, take out the sample. The sample is a sand strip that is 100mm long, 6mm wide, and 6mm high. The working layer is 4mm high, the support layer is 2mm high, and the groove of the U-shaped groove is 2mm wide.

[0082] 4. Dressing: Dress and grind the sanding strips on a grinding wheel machine;

[0083] 5. Testing: The hardness was tested using a Rockwell hardness tester (HRE: 118), and the diamond distribution density was measured using a microscope: 89 diamonds / mm². 2 .

[0084] The honing of cylinder liners using honing sand bars prepared in this embodiment is shown in the image below. Figure 5 As shown, by Figure 5 It can be seen that the honing pattern is evenly distributed and the intersection angle of the patterns is consistent.

[0085] Example 2

[0086] An economical and environmentally friendly U-shaped honing strip consists of a support layer and a working layer formed on the surface of the support layer;

[0087] The raw materials for preparing the working layer include: cobalt powder: 11%, copper powder: 32%, tin powder: 15%, iron powder: 9%, tantalum nitride: 22%, with a particle size of 20-30 μm for tantalum nitride, and the particle size of the other raw materials being less than 100 μm; the balance is diamond with a particle size of D54.

[0088] The raw materials for preparing the support layer include: copper powder: 78%, tin powder: 5%, silicon carbide: 15%, aluminum oxide: 3%, and tungsten powder: 3%; the particle size of all the above raw materials is less than 100 μm;

[0089] The preparation method of U-shaped honing strips specifically includes the following steps:

[0090] 1. Mixing: Weigh the different components according to the above ratio of the working layer and the support layer raw materials. Put the working layer raw materials and the support layer raw materials into the mixer respectively. Start the mixer and mix for 20 minutes respectively to ensure that the different components of each layer are fully mixed to obtain the working layer mixture and the support layer mixture.

[0091] 2. Mold assembly:

[0092] ① Weigh 12.5g of the support layer mixture, spread it evenly in the mold, and then level it with a scraper;

[0093] ② Weigh 23g of working layer mixture, spread it evenly on top of the support layer mixture, and level it with a scraper;

[0094] ③ Cover the mold with a cover plate that has a horizontal plate in the middle with a height of 4mm and a width of 2mm;

[0095] 3. Sintering: Sintering is carried out using a vacuum hot-pressing sintering furnace. The specific operation and parameters are as follows:

[0096] ④ Sample placement: Place the mold containing the mixture into the corresponding position inside the furnace, tighten the screw to press the sample, and close the cover.

[0097] ⑤ Vacuuming: Turn on the vacuum pump switch at this time, and when the vacuum reaches 200Pa, close the exhaust valve.

[0098] ⑥ Set pressure, temperature and holding time: Use the stepped sintering molding method. The first stage temperature is set to 450℃, holding time is 3min, and pressure is set to 20MPa; the second stage temperature is set to 650℃, holding time is 5min, and pressure is set to 30MPa; the third stage temperature is set to 750℃, holding time is 8min, and pressure is set to 35MPa.

[0099] ⑦ Pressurization: Once the settings are complete, turn on the press switch. When the pressure reaches 5MPa, turn on the temperature control system power switch. Heating begins at this point. When the set temperature is reached, hot pressing begins. Finally, after three heating cycles to maintain the temperature and apply pressure, the hot pressing sintering is complete when the maximum pressure is reached and the holding time is reached.

[0100] ⑧ Cooling and Demolding: After the entire process is completed, turn on the water chiller to cool the sand strip mold. After it has completely cooled, take out the sample. The sample is a sand strip that is 150mm long, 6mm wide, and 7mm high. The working layer is 5mm high, the support layer is 2mm high, and the groove of the U-shaped groove is 2mm wide.

[0101] 4. Dressing: Dress and grind the sanding strips on a grinding wheel machine;

[0102] 5. Testing: The hardness was tested using a Rockwell hardness tester (HRE: 122), and the diamond distribution density was measured using a microscope: 95 diamonds / mm². 2 .

[0103] The honing of cylinder liners using honing sand bars prepared in this embodiment is shown in the image below. Figure 6 As shown, by Figure 6 It can be seen that the honing pattern is evenly distributed and the intersection angle of the patterns is consistent.

[0104] Example 3

[0105] An economical and environmentally friendly U-shaped honing strip consists of a support layer and a working layer formed on the surface of the support layer;

[0106] The raw materials for preparing the working layer include: cobalt powder: 14%, copper powder: 32%, tin powder: 12%, iron powder: 7%, tantalum nitride: 28%, with a particle size of 20-30 μm for tantalum nitride, and the particle size of the other raw materials being less than 100 μm; the balance is diamond with a particle size of D54.

[0107] The raw materials for preparing the support layer include: copper powder: 83%, tin powder: 3.5%, silicon carbide: 8.5%, aluminum oxide: 4.5%, and tungsten powder: 1.5%; the particle size of all the above raw materials is less than 100 μm;

[0108] The preparation method of U-shaped honing strips specifically includes the following steps:

[0109] 1. Mixing: Weigh the different components according to the above ratio of the working layer and the support layer raw materials. Put the working layer raw materials and the support layer raw materials into the mixer respectively. Start the mixer and mix for 20 minutes respectively to ensure that the different components of each layer are fully mixed to obtain the working layer mixture and the support layer mixture.

[0110] 2. Mold assembly:

[0111] ① Weigh 8.5g of the support layer mixture, spread it evenly in the mold, and then level it with a scraper.

[0112] ② Weigh 14g of working layer mixture, spread it evenly on top of the support layer mixture, and level it with a scraper;

[0113] ③ Cover the mold with a cover plate that has a horizontal plate in the middle with a height of 4mm and a width of 2mm;

[0114] 3. Sintering: Sintering is carried out using a vacuum hot-pressing sintering furnace. The specific operation and parameters are as follows:

[0115] ④ Sample placement: Place the mold containing the mixture into the corresponding position inside the furnace, tighten the screw to press the sample, and close the cover.

[0116] ⑤ Vacuuming: Turn on the vacuum pump switch at this time, and when the vacuum reaches 200Pa, close the exhaust valve.

[0117] ⑥ Set pressure, temperature and holding time: Use the stepped sintering molding method. The first stage temperature is set to 450℃, holding time is 3min, and pressure is set to 20MPa; the second stage temperature is set to 650℃, holding time is 5min, and pressure is set to 30MPa; the third stage temperature is set to 750℃, holding time is 8min, and pressure is set to 35MPa.

[0118] ⑦ Pressurization: Once the settings are complete, turn on the press switch. When the pressure reaches 5MPa, turn on the temperature control system power switch. Heating begins at this point. When the set temperature is reached, hot pressing begins. Finally, after three heating cycles to maintain the temperature and apply pressure, the hot pressing sintering is complete when the maximum pressure is reached and the holding time is reached.

[0119] ⑧ Cooling and Demolding: After the entire process is completed, turn on the water chiller to cool the sand strip mold. After it has completely cooled, take out the sample. The sample is a sand strip that is 100mm long, 6mm wide, and 6mm high. The working layer is 4mm high, the support layer is 2mm high, and the groove of the U-shaped groove is 2mm wide.

[0120] 4. Dressing: Dress and grind the sanding strips on a grinding wheel machine;

[0121] 5. Testing: The hardness (HRE) was tested using a Rockwell hardness tester (116), and the diamond distribution density was measured using a microscope (96 diamonds / mm²). 2 .

[0122] The honing of cylinder liners using honing sand bars prepared in this embodiment is shown in the image below. Figure 7 As shown, by Figure 7 It can be seen that the honing pattern is evenly distributed and the intersection angle of the patterns is consistent.

[0123] Comparative Example 1

[0124] The composition of a U-shaped honing strip:

[0125] The raw materials for preparing the working layer include: cobalt powder: 12%, copper powder: 35%, tin powder: 13%, iron powder: 7%, and the particle size of the above raw materials is less than 100μm; the balance is diamond with a particle size of D54.

[0126] The raw materials for preparing the support layer include: copper powder: 80%, tin powder: 4%, silicon carbide: 10%, aluminum oxide: 4%, and tungsten powder: 2%; the particle size of all the above raw materials is less than 100 micrometers.

[0127] The preparation method is the same as in Example 1.

[0128] Testing: Hardness was tested using a Rockwell hardness tester (HRE: 98), and the diamond distribution density was measured using a microscope: 91 diamonds / mm². 2 .

[0129] The honing of cylinder liners using honing sand bars prepared in this embodiment is shown in the image below. Figure 8 As shown.

[0130] The absence of tantalum nitride in this comparative example affects the hardness and corrosion resistance of the honing abrasive strips. Due to the reduced hardness, the abrasive strips have poor wear resistance and faster granulation, thus shortening their lifespan.

[0131] Comparative Example 2

[0132] The composition of a U-shaped honing strip:

[0133] The raw materials for preparing the working layer include: cobalt powder: 12%, copper powder: 35%, tin powder: 13%, iron powder: 7%, tantalum nitride: 10%, and the particle size of the above raw materials is less than 100μm; the balance is diamond with a particle size of D54.

[0134] The raw materials for preparing the support layer include: copper powder: 80%, tin powder: 4%, silicon carbide: 10%, aluminum oxide: 4%, tungsten powder: 2%, and the particle size of all the above raw materials is less than 100μm;

[0135] The preparation method is the same as in Example 1.

[0136] Testing: Hardness was tested using a Rockwell hardness tester (HRE: 110), and the diamond distribution density was measured using a microscope: 93 diamonds / mm². 2 .

[0137] Comparative Example 3

[0138] A method for preparing honing strips:

[0139] The composition and preparation process of the working layer and the support layer are the same as in Example 1. In step 2, a flat cover plate is used for the mold cover plate. The sand strip sample is 100mm long, 6mm wide and 6mm high. The working layer is 4mm high and the support layer is 2mm high. There is no U-shaped groove.

[0140] Hardness (HRE): 120; Diamond density measured under a microscope: 90 diamonds / mm². 2 .

[0141] The honing of cylinder liners using honing sand bars prepared in this embodiment is shown in the image below. Figure 9 As shown, by Figure 9 It can be seen that the honing produced random patterns and inconsistent mesh angles.

[0142] Comparative Example 4

[0143] A method for preparing a U-shaped honing strip:

[0144] The difference between the composition and preparation process of the working layer and Example 1 is that diamond is replaced with silicon carbide, while other components remain unchanged.

[0145] The test results are shown in Table 1.

[0146] Comparative Example 5

[0147] A method for preparing a U-shaped honing strip:

[0148] The composition and preparation process of the working layer differ from those in Example 1 in that diamond and tantalum nitride are replaced with silicon carbide, while other components remain unchanged.

[0149] The test results are shown in Table 1.

[0150] Table 1 Performance data of honing strips prepared in each embodiment and comparative example

[0151]

[0152] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

[0153] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a U-shaped honing strip, comprising the following steps: S1) Mix the raw materials according to the proportion of the raw materials used to prepare the working layer to obtain the working layer mixture; The raw materials are mixed according to the proportion of raw materials used in the preparation of the support layer to obtain the support layer mixture; S2) After loading the working layer mixture and the support layer mixture into the mold, the mold is sealed with a cover plate; the working layer mixture is near the end of the cover plate, and the cover plate is a cover plate with protrusions corresponding to the U-shaped groove; S3) The mixture after molding is sintered to obtain U-shaped honing strips; The U-shaped honing strip includes: a support layer and a working layer formed on the surface of the support layer; a U-shaped groove parallel to the long side is provided in the short side direction of the honing strip; The raw materials for preparing the working layer, by weight percentage, include: 10-15% cobalt powder, 30-40% copper powder, 10-15% tin powder, 5-10% iron powder, 20-30% tantalum nitride, and 5-25% diamond; The raw materials for preparing the support layer include: copper powder, tin powder, silicon carbide, aluminum oxide, and tungsten powder; By mass percentage, the support layer contains 75-85% copper powder, 3-5% tin powder, 8-15% silicon carbide, 2-5% aluminum oxide, and 1-3% tungsten powder. The ratio of the distance between the two parallel sides of the U-shaped groove to the width of the U-shaped groove is (1~2):

6.

2. The preparation method according to claim 1, characterized in that, In the working layer, the content of cobalt powder is 11-14%; and / or, the content of copper powder is 32-37%; and / or, the content of tin powder is 12-14%; and / or, the content of iron powder is 7-9%; and / or, the content of tantalum nitride is 22-28%; and / or, the content of diamond is 7-15%.

3. The preparation method according to claim 1, characterized in that, In the support layer, the content of copper powder is 78-83%; and / or, the content of tin powder is 3.5-4.5%; and / or, the content of silicon carbide is 8.5-14%; and / or, the content of aluminum oxide is 3-4.5%; and / or, the content of tungsten powder is 1.5-2.5%.

4. The preparation method according to claim 1, characterized in that, In the working layer, the tantalum nitride has a particle size of 20-30 μm, and / or the cobalt powder, copper powder, tin powder, and iron powder each have a particle size of less than 100 μm; and / or the diamond has a particle size of 54-64 μm; and / or the diamond has a distribution density of 50-120 particles / mm² in the working layer. 2 .

5. The preparation method according to claim 1, characterized in that, In the support layer, the copper powder, the tin powder and the tungsten powder are each selected from particles smaller than 100 μm.

6. The preparation method according to claim 1, characterized in that, In step S1), the mixing time during the preparation of the working layer mixture is 10-30 min; and / or, the mixing time during the preparation of the support layer mixture is 10-30 min.

7. The preparation method according to claim 1, characterized in that, In step S3), the sintering includes a first sintering, a second sintering, and a third sintering performed sequentially; The temperature of the first sintering is 400~500℃, the holding time is 1~3min, and the pressure is 15~25MPa; The second sintering temperature is 600~700℃, the holding time is 5~7min, and the pressure is 28~32MPa; The third sintering temperature is 720~780℃, the holding time is 8~10min, and the pressure is 35~45MPa.

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